Juul maintains that its products are for adult smokers who want to move away from traditional cigarettes.

A recent study found that Juul stood out from other e-cigarette companies by marketing its devices on social-media platforms such as Twitter, YouTube, and Instagram.

That marketing campaign was a big success, the study suggests, with Juul's social-media activities being "highly correlated" with sales.

One big question about the booming Silicon Valley e-cigarette startup Juul is whether the company deliberately marketed its products to teens.

Juul has said that its sleek vaping devices are intended for adults trying to quit smoking traditional cigarettes — and that its marketing has had little impact on its sales. But a recent study raises some questions. It suggests that Juul's social-media ads — which were posted across platforms popular with young people including YouTube, Twitter, and Instagram — were a runaway success.

Public-health experts, scientists, and the Food and Drug Administration have been targeting vaping companies in recent months after dozens of reports suggested they were encouraging more young people to both vape and smoke. A handful of researchers have said a combination of the company's marketing efforts and product offerings — such as slick designs and sweet flavors — are intended to hook young people on nicotine.

The researchers behind the paper focusing on Juul, published this summer in the journal Tobacco Control, concluded that Juul stood out from other e-cigarette brands by advertising predominantly on social media, as opposed to places like on billboards or in magazines. And the campaign took off, according to the researchers, who wrote that sales of the flash-drive-style devices were "highly correlated" with the company's social-media posts.

The social-media campaign had another added benefit: It was cheaper than traditional marketing strategies, the researchers suggested.

The social-media blitz wasn't all directly from Juul, however, further complicating any efforts designed to help scale back the products' allure among teens. Several other corporate social-media accounts besides Juul's official platforms heavily promoted Juul products.

The overall impact was significant, the researchers concluded.

"Targeted cross-platform social media campaigns, although they cost little, can have substantial influence on people's attitudes, beliefs, and behaviors related to these products," they wrote.

'Taking advantage of the reach and accessibility of these platforms'

An ad on Juul's website from 2016.

Jidong Huang, an associate professor of health management and policy at Georgia State University who was lead author of the study, told The Washington Times over the summer that he felt the company's use of social media was a deliberate attempt to target young people.

Huang said Juul was "taking advantage of the reach and accessibility of these platforms to target youth and young adults," adding, "Basically everybody can see their product because there are no restrictions."

Juul has been adamant that its devices are not intended for young people.

"We cannot be more emphatic on this point: no minor or non-smoker/vaper should ever use Juul products," a Juul representative told Business Insider in an emailed statement. "Underage use is directly opposed to our mission of eliminating combustible cigarettes by offering the world's one billion existing adult smokers a true alternative."

Many social-media users, however, are young people.

Roughly half of teens ages 13 to 17 use Twitter, according to a survey conducted last year by the nonpartisan Associated Press-NORC Center for Public Affairs Research. That platform has been particularly lucrative for Juul, according to the researchers. YouTube is the most recognized content brand among kids ages 12 to 15, a 2017 report concluded. To that end, a Juul representative told Business Insider in July that the company had worked with Instagram to remove several accounts and thousands of posts that were inappropriately targeting youth.

But before then, a handful of social-media accounts — including Juul's official platforms — attracted the attention of thousands. And that attention appears to have had strong links to sales of Juul's products, the authors wrote.

In particular, the researchers found that the number of Juul-related tweets — most of which were posted last year — was "highly correlated" with the company's quarterly retail sales, which they tracked using data from market research company Nielsen. That said, correlation isn't necessarily causation. The researchers couldn't say that the tweets necessarily led to the sales, only that the two were linked.

"The growth trend in Juul tweets noticeably tracks well [with] the growth in Juul retail sales," the researchers wrote.

The relationship between Juul-related tweets and Juul sales was so strong, the authors found, that "the number of tweets alone accounted for 93% of the variation in Juul sales in retail stores." Put another way, the number of Juul tweets could be used to roughly predict how many Juuls would be sold at any given time.

'When you look at the flavoring names, one has to wonder'

A 2016 ad tells people to "Save room for Juul" and says its flavors are "easy to pair with your favorite foods." Juul According to Huang and his coauthors, Juul's official Instagram account, called JuulVapor, garnered tens of thousands of "likes" by evoking feelings of "relaxation, freedom, and sex appeal." While that strategy is somewhat standard in the advertising industry, something that made Juul's campaign stand out to the researchers was its emphasis on flavors.

At the time, those flavors included options like "Fruit Medley," "Cool Cucumber," and "Creme Brulee."

Several researchers have said that sweet, candy-like flavors are part of what makes e-cigarettes attractive to teens.

"Most scientists believe flavorings are used to target teenagers into becoming users," Ana Rule, a professor of environmental health and engineering at Johns Hopkins University, told Business Insider this summer.

"There are of course many other factors such as marketing and peer-pressure, but when you look at the flavoring names, one has to wonder."

Earlier this year, Juul changed the names of its flavor offerings. "Cool Cucumber," for example, is now simply "Cucumber"; "Creme Brulee" is now "Creme"; and "Fruit Medley" is now "Fruit."

"We have taken numerous actions to prevent and combat underage use, including focusing our website and social media exclusively on the adult smoker community and removing all product-related content from our social media accounts," the Juul representative said.

Doit4Juul: The most followed account for Juul products

Importantly, the new study found that the social-media blitz wasn't all Juul's direct doing. Beyond Juul's Instagram account, at least seven other accounts that promoted the Juul collectively amassed more than a quarter of a million followers on the platform, the authors wrote. And despite Juul's preventive actions over the summer, many of those accounts remain active in one form or another, Business Insider found.

One of the accounts was called "@Doit4Juul."

The account asked followers to share selfies, photos, and videos documenting themselves using Juul devices. And share they did. Images included youngsters jamming as many Juuls as they could in their mouths at once and then blowing out massive plumes of vapor; children openly using Juul devices in classrooms; and kids sharing tips on how to sneak the devices into school by encasing them in the bodies of Sharpie pens.

"This campaign proved highly successful," the researchers wrote, noting that the account amassed close to 82,000 followers and quickly became the most followed account featuring Juul products on Instagram as of February.

Over the summer, Juul worked with Instagram to remove the account, along with at least two others.

"We have aggressively worked with social media platforms to remove posts and accounts that portray our product in unauthorized and youth-oriented manners," the Juul representative said. "We stand committed to working with those who want to keep nicotine products out of the hands of young people."

But while the official account is gone, the #Doit4Juul hashtag remains active. Several similar accounts have also sprung up in recent months across the platform, including one called Doingit4Juul that shows several youngsters in braces and even in classrooms using the devices.

Using the hashtag symbol, anyone with an Instagram account can post to the series. At present, roughly 7,000 posts exist under the #Doit4Juul label alone. One of them features a young boy in a colorful shirt with a gold plastic crown on his head inhaling the vapor of two Juuls at once, then blowing out a large cloud.